1.2 Matter and Its Properties

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1.2 Matter and Its Properties
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Terms

• Matter- anything that has mass and volume
• Atom- smallest unit of an element that keeps the
  properties of element
• Element- pure substance made of only one type of
  atom
• Compound- substance made of 2 or more types of
  atoms that are chemically bonded
• Molecule- type of compound in which bonds are
  covalent bonds

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Properties of Matter

• chemists use characteristic properties to tell
  substances apart and to separate them
• some properties define a group of substances

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Types of Properties

• Extensive- depend on the amount of matter
• Ex volume, mass, amount of energy
• Intensive- do not depend on the amount
• Ex density, boiling point, ability to conduct

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Types of Properties

• Physical- characteristics that can be observed or
  measured without changing the identity of a
  substance
• Ex. melting point, boiling pt
• Chemical- relates to a substances ability to
  undergo changes that transform it into a
  different substance
• Easiest to see when a chemical is reacting

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Physical Changes in Matter

• change in a substance that doesnt change the
  identity of the substance
• Ex. grinding, cutting, melting, boiling
• Includes all changes of state (physical changes
  of a substance from one state to another)

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Solid

• definite volume
• definite shape
• atoms are packed together in fixed positions
• strong attractive forces between atoms
• only vibrate in place

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Liquid

• definite volume
• indefinite shape
• atoms are close together
• atoms can overcome attractive forces to flow

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Gases

• indefinite volume
• indefinite shape
• atoms move very quickly
• atoms are far apart
• pretty weak attractive forces

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Changes of State
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Plasma

• high temperature state in which atoms lose their
  electrons
• Ex. the sun

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Chemical Changes in Matter

• a change in which a substance is converted into a
  different substance
• same as chemical reaction
• doesnt change the amount of matter present
• reactants- substances that react
• products- substances that form

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Energy Changes in Matter

• when any change occurs, energy is always involved
• energy can be in different forms (light, heat,
  etc.)
• energy is never destroyed or created (law of
  conservation of energy)

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Energy Changes in Matter

• Exothermic Reaction- reaction that gives off
  energy (feels warm on outside)
• Endothermic Reaction- reaction that uses up
  energy (feels cold on outside)

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Separation Techniques

• Filtration- solid part is trapped by filter paper
  and the liquid part runs through the paper
• Vaporization- where the liquid portion is
  evaporated off to leave solid

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Separation Techniques

• Decanting- when liquid is poured off after solid
  has settled to bottom
• Centrifuge- machine that spins a sample very
  quickly so that components with different
  densities will separate

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Separation Techniques

• Paper Chromatography- used to separate mixtures
  because different parts move quicker on paper
  than other

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1.3 Elements
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Elements

• elements are pure substances
• organized by properties on periodic table
• each square shows the name and letter symbol for
  each element
• usually the symbols relate to the English names
  but some come from older names (usually Latin)
• Ex golds symbol is Au from aurum
• Ex irons symbol is Fe from ferrum

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Periodic Table

• Groups
• also called families
• vertical columns
• numbered 1?18
• have similar chemical properties
• Periods
• horizontal rows
• properties changes consistently across a period

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Periodic Table
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Periodic Table

• two rows below the periodic table are the
  lanthanide and actinide series
• these rows fit after 57 and 89
• they are only at the bottom to keep the width of
  the chart smaller

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Types of Elements

• Metals
• an element that is a good conductor of
  electricity
• at room temperature, most are solids
• malleable- can be rolled or hammered into sheets
• ductile- can be made into wire
• high tensile strength- can resist breakage when
  pulled
• most have silvery or grayish white luster

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Types of Elements

• Nonmetals
• an element that is a poor conductor of heat and
  electricity
• many are gases at room temperature
• some are solids usually brittle, not malleable

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Types of Elements

• Metalloids
• an element that has some characteristics of
  metals and nonmetals
• appear along staricase line
• B, Si, Ge, As, Sb, Te
• all are solids at room temperature
• less malleable that metals but less brittle than
  nonmetals
• are semiconductors

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Types of Elements

• Noble Gases
• generally unreactive gases
• in far right column of periodic table